


Tofu Hotpot (Gaster/Sans)

by idontevenknowugh



Series: Drowning in Drabbles [6]
Category: Undertale (Video Game)
Genre: Drugs, Electrocution, Genital Torture, M/M, Omorashi, Restraints, UF Sans/UF Gaster, UT Sans/UT Gaster, genital electrocution, nonconsentual drugging, nonconsentual experimentation
Language: English
Status: In-Progress
Published: 2020-06-29
Updated: 2021-02-28
Packaged: 2021-03-04 05:27:49
Rating: Explicit
Warnings: Graphic Depictions Of Violence, Rape/Non-Con
Chapters: 2
Words: 2,414
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/24988312
Author URL: https://archiveofourown.org/users/idontevenknowugh/pseuds/idontevenknowugh
Summary: Uggy's UF Sanster drabbles. Check chapter titles for Big warnings, summaries for detailed warnings.
Relationships: W. D. Gaster/Sans
Series: Drowning in Drabbles [6]
Series URL: https://archiveofourown.org/series/908838
Comments: 5
Kudos: 37





	1. Genital electrocution, experimentation, omorashi

"No..." Sans turned his face away from Gaster and the vial he was holding to his teeth. One of Gaster's many hands grabbed his chin roughly and forced him to face forward again. It pulled down, but he clenched his jaw as hard as he could to keep it from opening. The pressure grew painful, but, eventually, let up. Gaster was too impatient to wait for bones to heal. They'd both learned that last time. 

"What are you hoping to achieve by refusing me?" Gaster asked calmly, scribbling at his notes. "I thought you wanted to help find a cure for falling down." 

Sans had. He'd been willing, even excited, to work with the doctor to tackle such and important problem. Plus, the salary meant he had no trouble supporting Papyrus. It had seemed like a dream come true. It turned out, however, that Gaster hadn't been looking for a partner. He just wanted a body to test his experiments on. 

It had been fine at first, each paycheck making the bouts of nausea and restless nights worth it. Lately, however, the side effects had been getting worse. 

"Something else--!" Sans blurted, and the hand holding the vial managed to splash some of the swirling liquid into his mouth. He snapped his jaw shut and hoped it wasn't enough to have an effect. Last night had been hell, his dreams plagued by a too bright and colorful version of the world where everything was just a bit wrong. It had set him on edge so badly he woke up sweating. 

"Oh, are you the scientist now?" Sans whimpered and shook his head. It didn't matter if he was. Gaster didn't see anyone as equals. 

With a sneer, Gaster stood and walked over to a cabinet. The hand with the vial soared over to him and placed it inside. Gaster moved on to a desk where he opened up one of the drawers and began to dig through it. Things began to accumulate on the desk: a set of wires, a small box, and some kind of device. It was plain black with a few dials and knobs. Sans didn't like the look of it. 

"P--please," he stuttered as Gaster carried the items over to the table next to Sans. Four more of Gaster's hands currently held him down in a hard plastic chair. His tailbone ached from days of being stuck here the moment he walked into 'work'. 

Gaster ignored him. He plugged the wires into the device. The ends were odd, just plastic sockets. Sans's soul sank as Gaster opened the box and pulled out a small stack of pads. Sans hadn't ever used them, being completely disinterested in biology, but he had seen the electrode pads used by others. In Gaster's hands, they were terrifying. 

"Form your genitalia." 

"No!" Sans yelped. He tugged at the hands, but Gaster's magic was too strong. 

"That wasn't a request," Gaster stated slowly, as if he was talking to a particularly dull student. Sans shook his skull, trembling. He didn't want to have his magic anywhere near those pads. He didn't want it anywhere near Gaster. He had some kind of sick fascination with Sans's pussy. He never did anything sexual with it, but he loved to hurt it. 

"I'll do an--anything else," Sans wailed. 

"It's too late for that." 

Gaster shoved his hand between Sans's legs, cupping his pelvis. He rubbed with a blank expression and a clinical touch. Sans whined and wriggled as much as the hands would allow him. It wasn't much, and certainly not enough to let him get away from the cold hand. The methodical strokes up and down his pelvis still managed to wake his magic up. It warmed slowly, painstakingly, letting Sans feel ever soft shiver that Gaster evoked. His jaw clenched as a soft moan worked its way to it. 

When his pussy did actually form, Gaster withdrew his hand. He didn't even display pleasure at succeeding in forcing Sans to make it. He simply turned to the table and began to snap the pads onto the wires. Sans desperately tried to banish the magic from his pelvis, but he was too worked up. There was even a hint of liquid wetting the magical flesh. Maybe that meant the pads wouldn't stick. 

Gaster, of course, had thought of that. He faced Sans with four of the electrodes in one hand, and a cloth in the other. Roughly, he wiped Sans's magic, making a dry surface for two of the pads, one on the outer left lip, the other at the bottom of his pussy. Sans had to swallow a moan at the pressure of him pushing them on. Why did his body have to act like this? 

With the other two still in hand, one of Gaster's floating hands turned a dial on the black box up. A soft tingle started between the two pads. It might have even been nice, if Gaster hadn't been in control of it. Sans watched the hand anxiously. It kept turning, and the tingling got stronger. Sans wasn't ready for the moment that it turned painful. He gasped, even though it was mild, like a pinch that didn't end. Gaster raised an eyebrow, and the hand stopped. 

Tension drained from Sans's body. He wasn't out of trouble yet--he was never out of trouble-- but it was a reprieve. Careful not to disturb the two pads already in place, Gaster wiped him off again and put the other two on the right side and over his clit. So much for a break. Sans anxiously watched the hand, but another came to turn the second dial. Gaster wanted precise control over how much he hurt Sans, of course. 

He had almost gotten used to the mild pinching pain of the first set, but he was not at all prepared for the intensity of the second set. His clit felt good for a bare second before the electricity was too much for it. Jerking in the chair, Sans strained his body to move away from what was hurting it. The electrodes just tagged along, not that he got further than extending his spine up some. His arms and legs stayed firmly against the chair. 

"That little, hm?" Gaster commented, and wrote down some notes. Sans looked away, feeling weak. He shouldn't be this susceptible to Gaster's bullshit. He should be stoic, like Papyrus, his younger brother. He wasn’t, though, and it felt like he got weaker by the day. 

Sans wriggled with discomfort as Gaster wrote, but he was able to get used to this new shock. Eventually, his limbs relaxed, and he sat normally in the chair, even if he was shifting occasionally. 

Gaster glanced up at him, then down at his pussy. 

“Hm.”

That was never a good noise. Sans tensed just in time for the first set of electrodes to start stinging again. 

“Guh!” He grunted as the electricity went up much more quickly. Painful shocks traveled through his magic, then echoed in his soul. “Ah! F—fuck!” 

Gaster watched intently, but stayed impassive as Sans jerked against the hands. He only moved to write more notes. What was he hoping to learn? That electricity hurt? Sans arched up, his skull smacking into the top edge of the chair back. The ringing pain in his skull was still nothing compared to his pussy. It ached, magic twitching as the current sent it into spasms. 

"Gah! St--stop..." Sans gasped. "Please..." His body was getting tired from the constant pressure of the electricity. Gaster glanced up from his notes. He considered Sans, which was a step up from ignoring him. Surprisingly, the current lessened. Sans's joins relaxed and he sat in the chair again, still uncomfortable, but not in so much pain. 

"Your limit, already?" He scribbled something else down. "Can't your magic adapt?" 

Sans flushed, but he was relieved that Gaster had backed off some. It was no secret that Sans was weak, especially to Gaster. He had brought Sans to tears many times, already. Sans always tried to be stronger, but he also always gave up in the face of Gaster's cruelty. 

"Different areas may react differently," Gaster muttered. He turned to the remaining leads and plugged another one into the device. This one, he attached a simple metal post with a metal ball at the end. Sans watched anxiously as he fitted it into place, making sure it was secure, and then even taping it on with electrical tape. Where was that going? 

He figured it out the second before Gaster bent forward and pulled the lips of his pussy apart. 

"No! No no no!" Sans begged, shaking his skull. So much for backing off, Gaster had only given him a reprieve as he prepared to deliver the next level of pain. Gaster, of course, ignored him, but knowing it was futile didn't stop the stream of nos leaving Sans's mouth. 

The metal ball was cold as it was shoved into him. He winced, unsuccessfully trying to pull away from it. Gaster went further, his fingers dipping inside to make sure that the lead went as deep into him as it possibly could. His face twisted into disgust as he pulled just his fingers out and wiped them on a nearby rag. Sans wasn't even wet, since Gaster hadn't put any effort into arousing him this time. Sometimes he did, despite his constant disgust. 

"D--Doctor," Sans begged as a hand took hold of the next knob. Gaster didn't even look at him, and the knob began to turn. Electricity tingled deep inside of Sans. Slowly it grew, spreading out as the point of contact began to hurt. His magic didn't know what to do, between the five different points. It convulsed wildly. 

Sans rocked his skull against the chair, subconsciously looking for an outlet for the pain. A low moan of pain slipped out of his mouth. Pressure began to build in his magic, but nothing he was familiar with. It grew and grew until it was its own source of pain, as well, dull and throbbing. 

"Describe to me what you're feeling," Gaster demanded, his pen poised above the next page in his notebook. 

"Hurts..." Sans groaned, twisting his shoulders. 

"Describe it," Gaster huffed.

"I'm gonna... gonna burst..."Sans didn't know what the pressure meant, but he didn't feel good about it. His magic clenched, as much as it could, to keep it contained. Gaster frowned at him and scooted his chair back before the lead inside of his pussy was turned up even further. 

With a wail, Sans lost all control. Liquid began to dribble out of the top of his pussy, not from inside. This wasn't arousal, and there was a lot of it. The pressure eased slightly, and the trickle became a torrent, pouring out of Sans, and even arching up to splatter directly onto the floor. Gaster made another noise of disgust and slid further back. 

Sans let his skull hang down, at least one source of torment fading. The liquid was thinner than his arousal, too, though it had the light red tint of his magic. If he could gather the capacity to be concerned, he would be. Something was being removed from his body, and he didn’t even know what. 

“Very interesting,” Gaster commented and cleared his throat. Sans dragged his skull up enough to peek out the top of his sockets. The doctor was sporting a purple blush. It faded as he coughed a few more times, completely unnecessarily. Somehow, even though his magic still spasmed and pained grunts kept spilling out of his mouth, Sans felt better about not being the only one to lose his composure. It was the smallest of victories. 

Unfortunately, Gaster recovered much more quickly. He grabbed a test tube and crouched down to scoop up some of the liquid, careful not to get any of it on himself. Sans lost track of him as the prolonged current made his magic lock up it cramped, screaming with pain. Sans was the one screaming. He needed it to stop. 

The agony was so intense his mind shut down to protect itself. He lost vision, scent, taste, hearing, but it couldn’t retreat far enough to get away from touch, and the brutal indifference of the electricity, and the doctor. 

When Sans came to, Gaster was scowling and scribbling notes. The room was silent, except for the sound of the pen scratching and a faint ringing noise that wouldn’t go away. His magic was gone, as were the electrodes and the whole device. Despite its absence, there was a dull ache centered around Sans’s pelvis that reached up his spine and down his legs. Gaster’s hands were darting about, putting things away. Sans tested the freedom of his arms, lifting them off the arms of the chair and wiggling his fingers. 

The smell hit him once he noticed the large pool of reddish liquid spread out in front of him. He didn’t recognize it, but his hand twitched with the desire to cover his nasal aperture. 

“Oh good, you’re awake.” Sans froze at the doctor’s voice. What now? He shook, glancing up. Gaster hadn’t bothered to look at him, however. He was still writing, now interspersed with tapping at a calculator. Even so, he seemed to know he had Sans’s attention. Or maybe he just assumed. 

“Get dressed, clean this up,” he gestured at the liquid as if Sans had simply spilled something while doing his normal lab work. “You’re free to go after that.”

Dismissed, without the faintest idea what that had all been about. The question formed, born of the curiosity that had gotten Sans all the way to the royal labs. 

“Yes, Doctor,” he muttered ruefully as he stood to do as instructed.


	2. UT Sanster, angst

**Summary for the Chapter:**

> Warnings: angst
> 
> Inspired by one of the prompts for [Sanster week](https://twitter.com/hyliank8/status/1365315685275074561), Rendezvous.

It's not like Sans was looking for an excuse. Everyone knew he was lazy. The fact that no one knew about his shortcuts didn't matter. He was only using them because why would he walk to work when he could slip into the void at home and slip back out at his station. 

He rubbed his sternum, giving his soul a minute to stop aching so badly. Then he stepped into the darkness of nothing... almost nothing. A soft smile. A flash of white eyelights. Teeth met his for the barest second, then reality ripped him back into being... alone. 


End file.
